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Understanding Begins with Expressive Names

In 2018, I joined a large project halfway through its development. The original engineers had moved on leaving behind convoluted and undocumented code. Working with this type of code is challenging because you can’t differentiate the plumbing from the business domain. This makes debugging difficult and changes unpredictable because you don’t know the impact. It’s like trying to edit a book without understanding the words.

Many engineers believe the measure of success is when the code compiles. I believe it’s when another engineer (or you in six months) understands the ”why” of your code. The original engineers handicapped the future engineers by not documenting and using obtuse names. The names are sometimes the only window into the previous engineer’s thought process.

Donald Knuth famously said:

Programs are meant to be read by humans and only incidentally for computers to execute. – Donald Knuth

Naming

Naming is hard because it requires labeling and defining where and how a piece fits in an application.

Phil Karlton, while at Netscape observed:

There are only two hard things in Computer Science: cache invalidation and naming things.
— Phil Karlton

We see our code through the lens of words and names we use. Names create a language for the next engineer to comprehend. This language paints a picture of how the author bridged the business domain and the programming language.

Lugwid Wittgenstein, a philosopher in the first half of the 20th century, said:

The limits of my language mean the limits of my world. – Ludwig Wittgenstein

The language of our software is only as descriptive as the names we use and using vague names blur the software’s purpose; using descriptive names bring clarity and understanding.

Imagine visiting a country where you don’t speak the language. A simple request such as asking to use the bathroom brings bewildered looks. The inability to communicate is frustrating maybe even scary. An engineer feels the same when confronted with confusing, unclear, or even worse, misleading names.

This feeling is best experienced.

Experience

Examine the first snippet of code, what does this code do? What’s the why?

Take your time.

public class StringHelper
{
    public string Get(string input1, string input2)
    {
        var result = string.Emtpy;
        if(!string.IsNullOrEmtpy(input1) && !string.IsNullOrEmtpy(input2))
        {
            result = $"{input1} {input2}";
        }
        return result;
    }
}

The above code is a simple concatenation of two strings. What the code doesn’t tell you is the “why.” The “why” is so important, without it, it’s difficult to change behavior without understanding the impact. Of course, investigating the code’s usage will likely reveal it’s “why,” but that’s the point. You shouldn’t have to discover the code’s purpose, instead, the author should have left clues, it’s their responsiblity to do so.

Let’s revisit the code, but with a little “why” sprinkled in.

Again, take your time, observe the difference you feel when reading this code.

    public class FirstAndLastNameFormatter
    {
        public string Concatenate(string firstName, string lastName)
        {
            var fullName = string.Emtpy;
            if(!string.IsNullOrEmtpy(firstName) && !string.IsNullOrEmtpy(lastName))
            {
                fullName = $"{firstName} {lastName}";
            }
            return fullName;
        }
    }

The “why” brings the code to life, there’s a story to read.

Communicate

Communicating the intent and the design to the next engineer allows software to live and to grow because if engineers can’t modify the software, it dies. This is a tragedy, even more so when it’s a result of poor design and lack of expressiveness — each is preventable with knowledge.

Do the next engineer a favor and be expressive in your code. Use descriptive names and capture the “why” because who knows, the next engineer might be you.

You Are Not Your Code

It’s not personal.

Your code reflects neither your beliefs, nor your upbringing, nor your character.

Your thoughts and your opinions evolve, new ideas form, and you change. 

The you of today will be different from the you of tomorrow.

Embrace the difference, you and your code are better because it.

A General Ledger : Understanding the Ledger

What is a general ledger and why is it important? To find out read on!

What is a general ledger? A general ledger is a log of all the transactions relating to assets, liabilities, owners’ equity, revenue and expenses. It’s how a company can tell if it’s profitable or it’s taking a loss. In the US, this is the most common way to track the financials.

To understand how a general ledger works, you must understand double entry bookkeeping. So, what is double entry bookkeeping? I’m glad you asked. Imagine you have a company and your first customer paid you $1000. To record this, you add this transaction to the general ledger. Two entries made: a debit, increasing the value of your assets in your cash account and a credit, decreasing the value of the revenue (money given to you by your customer payment). Think of the cash account as an internal account, meaning an account that you track the debits (increasing in value) and credits (decreasing in value). The revenue account is an external account. Meaning you only track the credit entries. External accounts don’t impact your business. They merely tell you where the money is coming from and where it’s going.

Here is a visual of our first customers payment.

If the sum of the debit column and the sum of the credit column don’t equal each other, then there is an error in the general ledger. When both sides equal each other the books are said to be balanced. You want balanced books.

Let’s look at a slightly more complex example.

You receive two bills: water and electric, both for $50. You pay them using part of the cash in your cash account. The current balance is $1000. What entries are needed? Take your time. I’ll wait.

Four entries are added to the general ledger: two credit entries for cash and one entry for each the water and electric accounts. Notice the cash entries are for credits.

For bonus, how would we calculate the remaining balance of the cash account? Take your time. Again, I’ll wait for you.

To get the remaining balance we need to identify each cash entry.

To get the balance of the Cash account we do the same thing we did to balance the books, but this time we only look at the cash account. We take the sum of the debit column for the cash account and the sum of the Credit column for the cash account and subtract them from each other. The remaining value is the balance of the cash account.

And that folks, is the basics of a general ledger and double entry bookkeeping. I hope you see the importance of this approach. As it give you the ability to quicking see if there are errors in your books. You have high fidelity in tracking payments and revenues.

This is just the tip of the iceberg in accounting. If you’d like to dive deeper into accounting, have a look at the accounting equation: Assets = Liabilities + Owner’s Equity.

Hopefully this post has given you a basic understanding of what a general ledger is and how double-entry bookkeeping works. In the next post I’ll go into how to implement a general ledger in C#.

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